Drill spindle driving mechanism



p 9 5- v r w. G. HOELSCHER 2,384,745

DRILL SPINDLE DRIVliNG MECHANISM Original Filed July 28, 19398.Sheet-Sheet 1 Sept. 11, 1945. w. G. HOELSCHER 2,384,745

DRILL SPINDLE DRIVING MECHANISM Original Filed July 28, 1939 '8Sheets-Sheet 2 INVENTCR.

Sept. 11, 1945. w. G. HOELSCHER DRILL SPINDLE DRIVING MECHANISM OriginalFiled July 28, 1939 8 Sheets-Sheet 3 //l yl////l/// ///////////dll//// yIN VENT OR.

BY @744 Mama Sept. 11, 1945. we. HOELSCHER 2,384,745

' DRILL SPINDLE DRIVING MECHANISM Original Filed July 28, 1939 8LSheets-Sheet 4 INVENT OR.

Sept- 1945- w; HoELscHER 2,384,745

DRILL SPINDLE DRIVING MECHANISM Original Filed July 28, 1939 8Sheets-Sheet 5 U P 4 w. G..HO-ELSCHER- 2,384,745

DRILL SPINDLE DRIVING MECHANISM Original Filed July 28, 1939 8Sheets-Sheet 6 Sept- 1945' w. G. HOELSCHER 2,384,745

. DRILL SPINDLE' DRIVING MECHANISM Original Filed July 28, 1939 8 Sheets-Shee 7 EM" 5 wart Patented Sept. 11, 1945 DRILL SPINDLE DRIVINGMECHANISM William G. Hoelscher, Cincinnati, Ohio, assignor to TheAmerican Tool Works Company, Cincinnati, Ohio, a corporation of OhioOriginal application July 28, 1939, Serial No.

Divided and this application May 28, 1943, Serial No. 488,856

7 Claims. (CI. 77-33) This invention relates to machine tools and isdirected particularly to radial drills. The present application is adivision of my copending application Serial No. 287,132 entitled Drillspindle driving mechanism, and concerns the spindle feeding mechanism ofthe drill by which the spindle is advanced axially toward the work tofeed the tool into it.

One of the principal objectives of the present invention has been toprovide a radial drill head in which various parts of the feedtransmission control and tripping mechanisms are readily accessible forreplacement and repairs. The invention contemplates an assembly of feedtransmission gearing and gear shifting devices which is an integral unitbodily removable from thehead and contained within a bracket or framewhich is mounted in the head.

A further objective of the present invention has been to provideimproved mechanism for controlling and regulating spindle feed which maybe accurately disconnected at a predetermined point, for instance, whenthe tool has reached the proper depth.

Another objective has been to provide a structure in which the feed maybe discontinued at a fixed point relative to the range of spindle travelwhereby speed will be discontinued automatically if the depth settinginadvertently were such that it tend to advance the spindle beyond itsnormal range. In this respect the arrangement for feed connectioncontemplates a structure which will constantly maintain couplingmechanism in position whereby the clutch is automatically engaged afterthe adjustable stop dog is reset out of feed disconnection position.

Other objects and certain advantages of the invention will be more fullyapparent from the description of the accompanying drawings in which:

Figure 1 is a front elevation of a radial drill in which the presentinvention is incorporated.

Figure 2 is a sectional view taken on the line 2-2 of Figure 1illustrating the driving and feeding means for the spindle.

Figure 3 is a sectional layout view showing the spindle feedtransmission.

Figure 4 is a. sectional view taken on the line 4--4 of Figure 1 showingthe feed gearing in its actual position in the head.

Figure 5 is a sectional view taken on the line 5 5 of Figure 4,illustrating certain of the shift rods for the feed gears.

Figure 6 is a sectional view taken on the line 66 of Figure 4 showingadditional details of the shifting mechanism.

I Figure? is a fragmentary sectional view taken similarly to Figure 4but showing one of the shifts diagrammatically.

Figure 8 is a diagrammatic view of the speed shifting means. Figure 9 isa sectional view showing the telescopic arrangement of the shifter rodswhich are illustrated in elevation in Figure 8. Figure 10 is a sectionalview taken on the line Ill-l0 of Figure 4 showing the shifting cam inplan view.

Figure 11 is a view illustrating a development of the tracks of the camof Figure 10. t

Figure 12 is a front view of the head with the cover removed andportions broken away for illustrating details of the feed mechanism forthe spindle.

Figure 13 is a fragmentary front view showing a portion of the head toillustrate the feed control dial and control levers.

Figure 14 is a sectional view taken on the line 14-44 of Figure 12.

Figure 15 is a sectional view taken on the line l5l5 of Figure 12.

c Figure 16 is a vertical sectional elevation taken on. the line 16-46of Figure 12 illustrating more of the details of the head including thespindle counterweight and main feed control levers.

The generalconstruction of the radial drill in which the presentimprovements are disclosed includes a base I which has a stump 2 risingfrom one end thereof. A column 3 is rotatably mounted on the stump andhas a cap 4 attached to its upper end. An arm 5 is vertically slidablymounted on the column 3 and may be raised or lowered so as to place thearm in proper position for locating the drill at the desired heightrelative to the work. The work is mounted on the base I and the arm issupported and elevated by means of a screw 6 which depends from the cap4 of the column.

The drill head of the structure is indicated generally at l it isslidably mounted for longitudinal movement on the arm 5 which projectsradially from the column. For this purpose the arm is provided with arail 8 along its front face and a driven pinion 9 (Figure 2) ispositioned in the head to engage a rack l0 fixed along the rear face ofthe rail. The pinion 9 is rotated either by hand or by'power, forinstance, through means disclosed and claimed in a copending applicationSerialNo. 291,110, filed August 21, 1939, now issued as Patent No.2,295,516 entitled Head trav- .erse mechanism for radial drills.

The spindle of the tool is indicated generally at II and power for it isderived from an electric motor I2 which is mounted on the short end ofthe arm. Power is directed from the motor to a gear box (not shown)containing arm elevating gearing and its control means. From point poweris. carried without. break toasphned shaft. I3 (Figure 2) which passesthrough a speed transmission gear boX indicated generally at I4. Withinthe gear box I4 the power is. taken from the shaft I3 through suitablereversing clutches which are controlled by means of a main. powercontrol lever I5 for the drill head.

The shifting of the gearing for change in the.

speed of rotation of the drill is accomplished by shaft 31 and containsa shiftable cluster of gears 42, i3 and M which is slidably mounted uponit. Another vertical shaft 45 is mounted adjacent the shaft 4| and it,in turn, contains a driving gear 56 and a cluster of gears 41 and 48.The shafts it and Q5: are journalledtattheir endwise portions, inthecasing 21%;. j Gears $1. and 48 are not shiftable. Gear 43 on shaft 4|,however, is en ageable with the gear 41 while the gear 42 is Appropriateyokes areprovided for the shiftable gear clusters as described inthecopending application Serial No.

means of a lever I5 for shifting alternately to- 1 high and low-speedranges and levers ll and !8 which are movable with respect to a dialplate is for controlling shifting of appropriate gearsinthe selectedranges.

Details of the gearing and Shifting thereof, through which the speed ofrotation of the spindle is controlled, other thanthe details shown inFigure 2, are disclosed and claimedjinthe aforesaid patent applicationSerial No. 287,132 and, inasmuch as they form no part of the present.inventiom this subject matter is not repeatedhere. Briefly, how-ever,it, will, be noted that, the gearing in the speed box drives a shaftdrawn in dotted lines. and indicated at which, through additionalspeedchange gearing indicated generally at 2| (Figure 6) furnishespower. to" rotate the spindle I L.

Driving gear lfiwmeshes with a bull wheel 49 which is journalled uponroller bearings 50, the

inner races of the bearings being sustained upon a, sleeve 5! whichextendsupwardly from the lower portion of the head of the machine aroundis'from the pinion 46 to the bull wheel 49- through The feedtransmission gearing,v of which a layout is shown. in. FigureB; is.contained within a bracket unitindicated generally at. 2'2as describedat a. later point. in the. specification, the movement for the feedbeing derived from the spindle, thence. passing, through, thetransmission "contained in the bracket 12 to a feed pinion 23. engagedbetween rack teeth 24. offthespindle. atthe one side and teethon a.counterweight 5. at the other side. The feed gearing in. the preferredembodiment shown in the. drawings provides 16 different feeds and iscontrolled for. these changes by means. of. levers. 2.6 andv 2T at the.f'ac'evof the head (Figuresl and 13.); L'everZb' control'Sshifiingbetween. high and low-feed ranges,.whilelthe lower lever, ZI,accomplishes changes-in the. respective. ranges as. indicated on a dial281. The distance of, depthof feedli'sselected' from a. feed.- ing, and;dial indicator .29; I v

Connection. of. the feed. is, controlled, manually through leversMir-3B, and automatically by meansofj a dog 31 (Figure 12) Dogs. 3.232o'n av variable.counterbalance additionally control the spindle feed,keeping, it within normal; limits by automaticallyv stopping thefeeidiregardless of the hand. setting of the feed dial. A handy wheel133provides. for manual feeding. movement of. the spindle. while a, lever34 couples. either the. hand wheel or. the power feed.

As previously indicated, power is derived from the splined shaftI,3"through.transmission gearing in thebox Id'toashaftZD. (FigureZl.From this point power, passes through additional speed transmissiongearing, in the. housing 21 of the spindle II'.. Shaft 20 contains, abevel gear35 which meshes withthe bevel gear 35. attached to the upper,end ofiaverti'calsplinedshaft 3.T. This shaft is jj urnalledin bearings38--38'in the upper and lower walls, of the. housing 21'. A shiftablegear, cluster consistingof gears 39iand. 40 is slidably mounted" on the.splinedjshaft 3,'I;,while a splined shaft 4| is positioned'adiacent' thesplined the internal gear 52 to the gear-55, thence through the drivesleeve 58 to the spindle; A spindle bearing 5? is provided between thedrive sleeve and the sleeve 5| and packing indicated generally at58"also is provided to prevent the seepage of lubricant. A cap 59 ismounted to the headto enclose this structure;

The vertical structure for, the lower portion of the spindle justdescribed is employed because it enables, heavy lateral drivingthrustswhich normally would be imposed'upon the spindle tobe sustainedat the bull wheel journalwherebyaccu- Spindle feed.

As shown best in Figure 3 the drivesleeve 53 extends upwa-rdl'y aiongthespindleto an upper bearing 60 which i's-di'spesed within lug 61provided in the head casing; The upper portionof the spindle iscount'erturned 'as at 62 to carry a feed rack sleeve63 whichat-its-opposite-ends is supported upon bearings 64 and 65 respectively;the upperbearing 63 being'held beneath' a nutfili carried by thespindle, while-thelowerbearing'64 rests against a spindle shoulder. 7

The upper portionof the spindle passage i'n the head is providedwith asleeve 6-1 which carriesa' key 68 to engage a keyway 69 cut intothe-rack sleeve, whereby the sleeve ispermitted to movelongitudinallybut not: rotate. The? feed; pinion 23 engagesth'e' rack.teeth: out onathe racksl'eeve and it may beseen-therefore' that the.spindle may be advanced and retract'edi through this mechanismwhilethe-spindlerismotating. Just beneath the upper spindle bearing;Gil: a gear I0 is carried by-theidrive sleeve 53. I This gear furnishespower to. the. feed; transmission. i

The feed transmissiongear change unit is.containedwithin. the bracketZZ.and asaiwholeassembly, fits within the head. The bracket is attached tothe back wall" of the mainhead casing and is accurately positioned for,driving," angagement with the gear l0when it is secured in place. Thehead casing is a large and heavy unit whereas the bracket 22 is smalland, therefore may be cast and machined conveniently by productionmethods. In this improvement therefore extensive machining of the largehead casing is avoided and it is provided simply with machined seatsfrom which the bracket is supported. Aside from the facility which thisstructure lends to the manufacture of the machine it is also to beobserved that if repairs or replacements must be made in the feed'changegearing the bracket can be taken from the head as a unit, worked upon,then easily again installed.

The feed transmission shown in the drawings develops sixteen feedchanges and three splined shafts II, I2 and I3 are employed. Each of theshafts II, I2 and 13 is journalled vertically in bearings I4 at the topof the bracket and the shafts are held in position by means of nuts I5and a plate "I6 at their upper ends.

The first shaft II has a gear 11 mounted at its lower end beneath aflange I8 extending from the bracket. The flange contains a bearing I9which supports the lower end of the shaft and the gear is sustained uponthe shaft by means of a collar 80. Two slidable clusters of gears areprovided on this shaft which consists respectively of gears BI and 52,and 33 and 04. The second shaft I2 has two clusters of gears fixedthereto. One cluster consists of the gears 95 and 86 which are componentto the gears 3i and 82, while the other cluster consists of the gears 81and 88 which are component to the gears 83 and 84 respectively. Thegears 33 and 84 in the cluster are moved to either of two positions bymeans of a yoke 89 (Figure 8) which engages an annular groove in thecluster and in turn is fixed to a shift rod 90. Gears BI and 82 areshifted by means of a yoke M which engages an annular groove in thecluster and is fixed to a tubular shift rod 92 within which the shiftrod 90 is telescopically engaged. Through these gears 4 speeds may beimparted to the shaft I2.

The third shaft, I3, of the feed transmission has a gear cluster fixedthereto consisting of the gears 93 and 94. Gears 95 and 95 contained onthe intermediate shaft I2 are component to gears 93 and 94 and thiscluster is shifted by means of a yoke 91 (Figures 4 and 7) which isfixed to a. shift rod 98. Shaft I3 is journalled in a lug 99 of thebracket 22 above the gears 93 and 94 and a sleeve is disposed aroundthis shaft between the bearing at the top and the bearing in lug 99. Theshaft extends down below the gear cluster 93, 94 and is journalled in abearing I00 contained within a lug IOI near the bottom of the bracket.

A gear I02 is loosely rotatably mounted on the shaft I3 just below thecluster of gears 93, 94. This gear has a hub of substantial diameterwhich is supported on a bearing I03, the inner race of which is fixedbetween a shoulder on the shaft and a sleeve I04 engaged against thelower end of the cluster of gears 93, 94.

Just below the gear I02 the shaft I3 is splined to slidably carry a gearI05. This gear is shifted from one feed range to another by means of thelever 26 which is provided at the head of the machine for this purpose.A yoke I06 (Figure 6) is fixed upon a slide rod I01 to engage an annulargroove I08 in the gear I05, while the lower end of the shaft I3 carriesa nut I09 which rests against the bearing I00 in the lower sustaininglug.

Gear I02 is constantly in mesh with a cluster of gears IIO, III which isrotatably mounted on a shaft II2. This shaft has its upper endjournalled in a bearing II3 within the bracket 22 at a position adjacentthe lug I9 while the lower end of the shaft is journalled in a bearingH4 in the lower bracket wall. Shaft I I2 is in alignment with shaft 12and the lower end of the latter shaft is sustained in a bearing II5which is disposed adjacent the bearing I I3. A shiftable gear H6 isslidably mounted on the shaft H2 and is in constant sliding mesh, asshown by the dot and dash lines in Figure 3, with a gear III. Gear IIIis fixed to a worm shaft IIB which is journalled at its opposite ends inlugs II9 extending from the bracket. A worm I20 is keyed to the shaft H8and meshes with a worm wheel I2I (see Figures 3 and 12). This wheel ismounted on a shaft I22 and, through a clutch, drives gear I23 whichmeshes with a gear I24 on another shaft I25 (Figure 12). Gear I24 mesheswith a large gear I26 fixed to a shaft I21 carrying drive pinion 23.

Gear I02 is provided with internal teeth I28 for meshing engagement ofgear I05 therewith while the gear III of gear couplet H0, III on shaftI2 also is provided with internal teeth for engagement with gear II6.

High and low-range feeds to the spindle are imparted by shifting thegear I05 to engagement with the internal teeth I28 of gear I02 or, asshown, for the low-range of feeds, with the internal teeth on gear III.For the high-range of speeds the drive comes from the shaft I3 throughgear I05 to the internal teeth I28 of gear I02, to gear IIO, thencethrough the internal teeth on gear I II to gear IE5 which is in slidablemesh with gear I II. The low-range gear I05 is connected directly to thegear III and through its internal teeth to gear II'I.

Shaft II2 has another gear I29 which is free to rotate on bearings I30carried by the shaft. This is a hand feeding gear in mesh with handfeeding means 33. shiftable gear II6 has clutch teeth I3! at its lowerface which are arranged to mesh with clutch teeth I32 of the gear I29.Gear I 56 also is provided with an annular groove engaged by a yoke I33(Figure 4) which is mounted on a rod I34 (Figure 15) slidably supportedin the bracket 22. The yoke I33 is shifted from power couple to handcouple through lever 34 at the front of the head.

The intermediate shaft I2 may be driven at four different speeds, theshaft I3 at eight. Two ranges of eight speeds each are provided at theshaft II2 by shifting of the gear I05. Therefore it may be seen thatsixteen feed changes may be imparted to the spindle.

Spindle feed shifting means The lever 2! at the head of the machineincludes, as shown in Figures 4 and '7, a balll35 approximately midwayof its length whereby the lever is mounted for movement in compounddirections substantially in the plane of a dial plate I36 containingfeed indications. This lever has an operating knob at its outer end anda coupling knob I31 at its inner end. The socket within which the ballI35 is mounted is split consisting of elements held together and alsoheld to a lower extension I38 of the bracket 22. These elements, I39,are disposed in the cover plate and carry a packing ring encircling theball.

The feed indication plate I36 has two ranges indicated across its upperportion while feed indiciais displayedat the central portion of thepane. At each side of the upper panel arrows pointing in oppositedirections indicate low feed at the l'eft hand side and high feed at theright-- hand side.- Since the shaft to which the range control lever isattached is on an axis aboveand in vertical alignment with the ball andsocket lining of the lower lever 21, it will be seen that this lever,depending to a point adjacent the indicator panel, will liesubstantially above the range indicating panel. Its effective positiontherefore can be determined at a glance. Further details of this subjectmatter appear in the copending application Serial No. 287,132.

The lever 21 operates a cam I60 which-,- as shown in Figures 4 and I0,is essentially in the form of a segment of a cylinder. This segment ismounted axially on a shaft IM journal'led in flanges of the bracket 22"so that the forward face I4-2 of the cam I40 may swing with respect tovarious yoke: actuating elements. The connection between the lever 21and the cam provides for horizontal and vertical shifting of the leverwithout disturbing the operating couple between these parts. For thispurpose a stud I43 is slidable vertically in a boss I44 which isprovided adjacent thesurface M2 of the cam. The stud has a headed rollerend whichis slotted as at I 45 to receive the operating ball I31 of thelever. The lower end of this stud also is provided with an annular slotI46 which is engaged by a yoke M1 which is fixed to the lower end ofshifter rod 98 which carries the yoke 91 for shifting gears 95, 96 ofthe couplet. The cam has four lateral, or horizontal, positions anddetent means is provided for holding the cam inthese loca-' tions. Forthis purpose the cam is equipped with a plate I48 which extends acrossits upper surface and which has four notches in its edge. An arm I49pivoted on a pin I 56 fixed in a cross web I5I= carriesa roller I52 forengagement with the notches in the detent-bar. Coil spring I53 interconnects the outer end of the arm- Hi8 withapin I 54 extending from thebracket to urge the roller against the grooved edge of the bar.

The range shifting lever 2-6 located just above the feed lever 21' isfixed to's-tud shaft I55 (Figure 4) which is journalled in a bushing wein the front cover I51 fthe head. Thiscoveris placerin front of the feedtransmission carried by the bracket 22.

Referring to Figures and 6' the slide rod 91, which. operates yoke I95for shifting. gear I535; is

elements rod 98; is suspended from a tension spring t69- which has itsupper end supported from the plate at the top of the bracket assembly.

nicvedby means of an arm I58 extending from a shaft I53 leading to thefront of the head. Since this range changing yoke has two positions therod I01 includes two grooves- I60 appropriately spaced apart andarranged for engagement by spring actuated detent bars I6I which arepositioned in the bracket. At the forward end of the shaft I59 it isattached to operating shaft I of the lever 26 by means of arms I62 andIE3 mounted on the respective shafts and connected by a link I56: Thisinterconnection is shown in Figure 12.

The vertical shifter rod 98- controlling' the cluster of gears 95 and:96 has two positions and: is held in: either one by means of a detentI55 (Figure 5) sustained by a spring-urged detent lever IE6 which issuspended from the shaft I59- whereby the detent is urged towarddetentnotches I61 cut in the side of the rod 98; This rod also is cut away asat I-68 for clearance of .the dctent arm. For coun-terbalancing theweight ofthe gears 95 and' 96 and the associated shifter Rods 98' and92' which shift the upper clusters of. gears 83, 84 and 82, M aretelescoped, one being slidable within the other, as shown best Figures 8and 9. The lower end of each ofthese shifting rods carries a collar I10and each collar has a pin extension I1I which respectively engages thecam tracks out inthe shaft I42 of the cam- I40. A coil spring I12resting on a cross member I13 of the bracket unit supports the yoke 9|and therefore counterbalances the weight of the gears BI and 82 andtheir shifter unit. For suspending the gears 83 and 84' and the innershifter rod and yoke thereon, the yoke 89 has a stud I14 projecting fromit which is supported in a tension spring I15 depending from the plate16 of the bracket, alongside the spring I69.

The spindle is raised and lowered manually by means of the handwheel 33which is fixed to the lower end of a shaft I16 in a vertical box orbracket I11 (Figures 10 and 15) fixed to the side of the head. The upperend of the shaft carries a gear I18 which is in mesh with another gearI19 carried by this bracket. The gear I19 meshes with gear I29 of thefeed assembly.

As previously explained, when gear IIB of the feed transmission is inits lower position it is clutched with the gear I29 for hand feeding ofthe spindle. The return to neutral is accomplished either manually orautomatically by power. Manual shifting takes place through the lever 33. As shown in Figure 16, this lever is mounted upon a shaft I85 whichpasses through a bushing I8I at the front head cover plate; the shaft isjournalled additionally in a bearing disposed in a front web of thebracket 22. The shaft also is j'ouriialled' in a plate I82 which isfixed to the bracket 22 intermediate the cover and the rear bearing. armI83 extends from the stud shaft I86 into connection with a shifter link-I8 lwhi'ch extends upwardly inside the cover plate. The link I 8'4intermediate its length is provided with a pivot pin I85 for rocking an"arm I86 which is mounted for rotation en the shaft I59; (See Figure12'.) The arm I86 has" a roller 81 fixed to its rear surface (Figure 15)which engages a cross slot in the yoke I33 whereby gear H6 is shifted. Adetent plate I88 projects from the arm I86 and has notches I89 cut inits surface which are engaged by a roller projecting from a detent leverHill which is pivoted upon the bracket 22', while the opposite end ofthe lever I90 is under the tension of a spring IS'I. From thisdescription it may be seen that shifting of the hand lever 3'4 betweenthe positions shown in Figure '13 actuates the gear H6 to accomplish achange between power and hand feed.

Feed control dog 31 which is provided in the adjustable rotatabledialelement of the feed system may be set for interrupting the feed at adesired point. This dog engages a roller I92 which is carried by the armI8 3 which forms a part of the coupling system just described. The dog3'! is effective for shiftingthe couplingsystem to a neutral positionintermediate the detent notches; The feed also may be interruptedautomatically at upper-and lower limits ofspindle travel by means of acounterbalance mechanism explained at a later point in thespecification- It may be seen from Figure 16 that the gear 23 whichmeshes with the rack 24 of the spindle assembly is supported upon ashaft, I21 which in turn carries the gear I26 of the layout shown inFigure 3 at itsforward end. This assembly ismounted in front and backbearings I95.

The dial element 80 at the front of the head carries graduations whichmove with respect to an indicator point. This dial element is rotatablyand adjustably mounted on the enlarged forward end of the shaft I22which carries gear I23 as a part of the feeding gear train. Shaft I22also carries a clutch which is effective for coupling the worm wheel I2Ito the shaft I22 and therefore to the feed pinion 23.

The clutch is actuated by means of the diametrically extended handlevers 38-36 which pivotally are mounted on pins I56 of th shaft I22 asshown in Figure 2. These levers provide manipulating knobs whereby theoperator may clasp either member and by pulling it outwardly engage theclutch. The clutches are of selfmaintaining type and once they are swunginto engaged position the clutch will remain until manually released.

The inner ends of the levers 3Il30 are connected to the outer end of aclutch actuating rod I91 which is slidably mounted in a central bore inthe shaft I22. The shifter rod I91 carries a roller I98 disposed in alongitudinal slot or keyway in the internal bore of the shaft I22 toengage an inclined or cam surface on the end of a clutch actuating leverI99. This lever, pivoted at its outer end, is held downwardly againstthe roller by means of a coil spring 200. The outer end of the lever isformed for engagement with the end of a split clutch ring 25H. The outerend of the clutch ring is pointed and the receiving surfaces of thebluntly pointed end engage corresponding surfaces of adjustment elements202 which are adapted to be moved toward and from the receiving surfacesby means of a rod 293 extending to the front of the dial through asleeve 204'. Tightening or loosening of the nuts carried on the forwardend of this rod draws the adjustment elements closer together or permitsseparation thereof by means of a suitable coil spring.

The outer ends of the clutch rod I91 includes a locking disc 286rotatably mounted on a screw 20'! extending axially into the end of therod. This locking disc, when turned to a position determined by detentsin the end of the rod, prevents engagement of the clutch by preventingmovement of the levers 30. The split ring 20I is keyed to the shaft I22and the worm wheel I2! of the feed system is loosely journalled on theshaft I22 through bearings 228 to house the clutching arrangement justdescribed. The adjustable dial ring 29 is fixed to the shaft I22 bymeans of the clamping device 209.

Thus, in the system just described, the gear I2I, unclutched, may rotatefreely on. the shaft I22. However, when this gear is clutched to theshaft through manipulation of the levers 30 and is being driven throughthe worm I 20 of the feed transmission the movement is conveyed to theshaft I22, thence to the gear I23 which is keyed to the shaft as shownin Figure 2. From this point the power passes to gear I24 which isjournalled in the head, and on up through gear I26 whereby the feedpinion 23 is driven to advance the spindle.

The head includes an adjustable counterbalance shown in Figure 12 whichis adapted to accommodate for variations in the weight of the toolscarried by the spindle. This counterbalance acts upon a pinion 2I0 whichis fixed to the outer end of the shaft I21 which carries the feed pinion23. A segmental internal gear 2II meshes with the pinion 2I0 and rotatesabout a stud 2I2 fixed to the casing which provides a double rollerbearing support for it. A heavy coil spring 2I3 under tension between astud 2M of the segemental gear and an adjustable stud 2I5 applies thecounterbalancing force. The adjustable stud 2I5 is disposed in abifurcated nut 2H3 which is traversed by means of a screw 25'! rotatablymounted at the top of the head casing. The crank handle 2I8 is pinned tothe forward end of the screw rod at the side of the head casing.

It may be seen that when the counterbalance spring 2I3 is at itsoutermost position with respect to the pivot 2I2 it will providecounterbalance for a heavy boring tool. The dot 'and dash lines show theposition at which it may be set when no boring tool is contained withinthe chuck. This aspect of the present invention is disclosed and claimedin a separate application, Serial No. 297,722, filed October 3, 1939,now issued as Patent No. 2,278,262.

It may be noted, however, that the segmental gear 2i I also provides thespaced lugs 32 which, by engagement with an uncoupling lever 2I9, limitsthe range of movement of the spindle. The lever 2!!! includes two arms,one of which carries a roller 220 arranged for engagement alternately bythe lugs 32. The other arm includes a set screw 22I adapted to engagethe upper end of link I84 for moving the gearing into neutral forstopping spindle feed.

The lever 2I9 is mounted on an eccentric bearing 222 which may be moved,in assembly of the head. for adjustment of the positions at whichspindle feed is discontinued at predetermined limits. The eccentricbearing is fixed in position by means of a disc 223 which has a pinengaged in any one of a number of holes which otherwise may be used toreceive a spanner wrench.

Having described my invention, I claim:

1. In a head for a radial drill, including the drill spindle and thesource of power, a single bracket fixed within the head, a feed geartrain mounted in said bracket for translating said spindle, means fordeclutching the gear train, means carried by the feeding mechanism foroperating said declutching means at a predetermined point, a rack andgear for translating the spindle, said gear driven by said gear train, a

. spring urged gear segment in mesh with a gear carried by the rack gearand counterweighting the rack gear, and dogs on said segmental gear forstopping the feed at the upper and lower limits of spindle travel, allof said parts, with the exception of the segmental gear, carried by saidsingle bracket.

2. In a head for a radial drill, including the drillspindl and thesource of power; a feed gear train mounted in said head for translatingsaid spindle, adjustable means for declutching said feed at apredetermined point, a rack and gear for translating the spindle, saidgear driven by said gear train, a gear segment in mesh with a gearcarried by the rack gear for counterweighting the rack gear, and dogs onsaid segmental gear for stopping the feed at the upper and lower limitsof spindle travel.

3. In a radial drill head including a spindle; a spindle feedtransmission consisting of a series of shiftable gears and means foruncoupling said transmission, a segmental gear in mesh with a gear ofsaid transmission and limit dogs on said segmental gear for operatingsaid uncoupling means for uncoupling said transmission at the upper andlower limits of spindle feed.

4. In a drill head for a radial drill having the casing and drillspindle assembly in the casing; a feeding transmission for feeding saidspindle, a clutch in said transmission for uncoupling the transmission,a counterweight lever engaging a gear of the feed transmission, saidlever including spaced lugs, and a tripping means connected to theclutch and adapted to be actuated by said lugs at the upper and lowerlimits of travel of the spindle.

5. In a radial drill head including the drill head casing and thespindle asssembly in the casing; a spindle feeding transmission, anuncoupling means therefor, a single bracket for supporting saidtransmission and uncoupling means in driving relationship with thespindle assembly, a counterweight lever pivoted in the a arid having ame h n e ga eme wi h a gear of the transmission, said lever includingspaced lugs, an operating lever pivoted on the bracket and engageable bysaid lugs, said lever connected to said uncoupling means and means foradjusting the position of the lever with respect to the lugs.

6. In a-tool spindle operating head for a radial drill, including thegear change transmission; a cam, a rotatably shiftable cam leverconnection from said cam to said gears, a lever for shifting said cam,and a connection between said cam and lever shiftable axially of the camfor feed speed range change.

7. In a tool spindle operating head for a radial drill, including thegear change transmission; a cam, a rotatively shiftable cam leverconnection from said cam to said gears, a lever for shifting said cam, aconnection between said cam and lever shiftable axially of the cam forfeed speed range change, a panel including rows of feed speed markings,and said lever having a knob adapted to be positioned in front of theparticular marking showing the feed speed de-

